Free Access
Reprod. Nutr. Dev.
Volume 46, Number 5, September-October 2006
5th annual INRA-Meeting: Mammary gland and milk
Page(s) 463 - 480
Published online 23 September 2006
Reprod. Nutr. Dev. 46 (2006) 463-480
DOI: 10.1051/rnd:2006032

Feeding and circadian clocks

Lissia Pardini and Bertrand Kaeffer

CRNH de Nantes, INRA - PHAN (UMR 1280), Rue de la Géraudière, BP 71627, 44316 Nantes Cedex, France

(Published online 23 September 2006)

Abstract - The mammalian genome encodes at least a dozen of genes directly involved in the regulation of the feedback loops constituting the circadian clock. The circadian system is built up on a multitude of oscillators organized according to a hierarchical model in which neurons of the suprachiasmatic nuclei of the hypothalamus may drive the central circadian clock and all the other somatic cells may possess the molecular components allowing tissues and organs to constitute peripheral clocks. Suprachiasmatic neurons are driving the central circadian clock which is reset by lighting cues captured and integrated by the melanopsin cells of the retina and define the daily rhythms of locomotor activity and associated physiological regulatory pathways like feeding and metabolism. This central clock entrains peripheral clocks which can be synchronized by non-photic environmental cues and uncoupled from the central one depending on the nature and the strength of the circadian signal. The human circadian clock and its functioning in central or peripheral tissues are currently being explored to increase the therapeutic efficacy of timed administration of drugs or radiation, and to offer better advice on lighting and meal timing useful for frequent travelers suffering from jet lag and for night workers' comfort. However, the molecular mechanism driving and coordinating the central and peripheral clocks through a wide range of synchronizers (lighting, feeding, physical or social activities) remains a mystery.

Key words: mammals / human / circadian rhythms / nutrients

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© INRA, EDP Sciences 2006